Search PubMed⌕ Search

Biomedical subjects

G Gabbiani

Publications and source records attributed to G Gabbiani.

At least 199 records · Page 11Linked to original sources
PubMed1985

Remodeling of the aortic smooth muscle cell cytoskeleton during developmental and pathological conditions.

The remodeling of aortic smooth muscle cell cytoskeleton has been investigated qualitatively and quantitatively during rat aorta development and experimental or human atheromatosis, using immunofluorescent and biochemical techniques. The cytoskeleton of smooth muscle cells in the intimal thickening 15 days after endothelial removal and in human atheromatous plaque is very similar to that of poorly differentiated aortic smooth muscle cells of foetal and newborn rats. Our studies suggest that cytoskeletal changes (a switch in the synthesis of actin isoforms in particular) are reliable markers of proliferative aortic smooth muscle cells, and of atheromatous smooth muscle cells.

Animals↗
PubMed1985

Cytoskeletal features of rat aortic cells during development. An electron microscopic, immunohistochemical, and biochemical study.

Actin, vimentin, desmin, and tropomyosin distribution in rat aortic endothelial and smooth muscle cells has been studied during development using fetal (18 to 20 days of gestation), and 5- and 14-day-, and 5-, and 12-week-old rats. Endothelial cells of newborn animals actively replicate and contain many actin stress fibers, whereas, in adult animals, replication is minimal and actin stress fibers are rare. The actin, vimentin, desmin, and tropomyosin content of smooth muscle cells increases gradually from fetal to adult animals. The number of desmin-containing cells also increases from 13% in fetal rats to 51% in adult rats. The beta-actin isoform is predominant in fetal and newborn animals, but gradually the alpha-isoform becomes quantitatively the most important, as seen by bidimensional polyacrylamide gels. Several analogies exist between the features of developing smooth muscle and what is known for developing striated muscle cells. The evolution of cytoskeletal features from fetal to adult animals is remarkably the opposite of what takes place in: (1) rat aortic smooth muscle cells proliferating after an endothelial injury, (2) human arterial smooth muscle cells present in atheromas, and (3) actively growing rat aortic smooth muscle cells in vitro. Thus, the assumption that pathological or cultured smooth muscle cells are "dedifferentiated" is supported by our biochemical observations.

Actins↗
PubMed1985

Expression of class II transplantation antigen on vascular smooth muscle cells in human atherosclerosis.

A large proportion of the cells of the human atherosclerotic plaque is assumed to be derived from medial smooth muscle cells. In contrast to these, the cells of the plaque have the capacity to accumulate lipid, and they also proliferate at a higher rate than medial cells. It has therefore been suggested that smooth muscle cells undergo a change of phenotype during atherogenesis, but there has been no evidence for such a change on the molecular level. We have now analyzed carotid artery plaques using a battery of antibodies against cell surface and cytoskeletal antigens, and found that most of the cells express the class II transplantation antigen (Ia antigen) HLA-DR. Also, the beta chain of HLA-DR was detected by immunoblotting of plaque extracts with the OKIa1 monoclonal antibody. HLA-DR is normally present on cells of the immune system, but only 60% of the DR-positive cells of the plaque reacted with monoclonal antibodies specific for macrophages and lymphocytes. Many of the remaining DR-positive cells contained the muscle-specific intermediate filament protein, desmin. This indicates that smooth muscle cells of atherosclerotic plaques express DR antigen. In contrast, very few DR-positive cells were found in normal human arteries. This suggests that expression of class II antigen is part of a phenotypic change in smooth muscle cells in atherosclerosis.

Aged↗
PubMed1985

Aortic endothelial cell during regeneration. Remodeling of cell junctions, stress fibers, and stress fiber-membrane attachment domains.

We have studied in regenerating endothelium of rat thoracic aortas (a) organization of tight and gap junctions by means of morphometry using freeze-fracture electron microscopy, (b) development of cytoplasmic actin microfilament bundles (stress fibers) by means of morphometry using thin section electron microscopy, and (c) distribution of filipin-sterol complexes in the endothelial plasma membrane using thin section and freeze-fracture electron microscopy. The index of complexity for tight junctions and the index expressing the average width of gap junctions were significantly higher in regenerating endothelium than in normal aortic endothelium. In regenerating endothelium, there was a significant increase of the stress fiber to endothelial volume density ratio as compared to normal. Stress fibers were connected to cytoplasmic microfilament condensations located at the abluminal plasma membrane; the surface density of these condensations was significantly increased in regenerating endothelium as compared to normal. Filipin-cholesterol complexes were few or absent at stress fiber-membrane attachment sites but numerous in the remaining endothelial plasma membrane. This morphologic remodeling of the aortic endothelial cell layer may help to explain changes of endothelial cell function occurring in situations associated with increased cell turnover and motion.

Animals↗
PubMed1984

The intermediate filament cytoskeleton of myofibroblasts: an immunofluorescence and ultrastructural study.

The intermediate filament cytoskeleton of stromal myofibroblasts from a series of twenty-eight infiltrating ductal breast carcinomas was examined by transmission electron microscopy (TEM) and indirect immunofluorescence (IF), the latter using antibodies to desmin, vimentin and prekeratin. Three cases of fibromatoses, selected as an additional source of myofibroblasts, were processed in the same manner. Stromal myofibroblasts from invasive ductal breast carcinomas rich in actin and readily identified by IF, were most numerous in the "young" edematous mesenchyme, areas corresponding to early stromal invasion or the peripheral invasive cellular front. Within the central sclerotic zone wherein clusters of neoplastic epithelial cells were surrounded by abundant collagen, most stromal cells corresponded by TEM to fibroblasts. In like fashion, myofibroblasts were most numerous in cellular, poorly collagenized portions of fibromatoses. By IF the only detectable intermediate filament protein of myofibroblasts in these two settings was vimentin. Since the appearance of stromal myofibroblasts appears to be associated with stromal invasion by malignant epithelium, their development by modulation of pre-existent periductal fibroblasts is postulated. With the exception of vascular smooth muscle cells and endothelial cells, the only periductal mesenchymal cells shown to contain vimentin were fibroblasts. The lack of desmin in myofibroblasts constitutes evidence against an origin from vascular smooth muscle cells. Because the molecular markers (intermediate filament proteins) of stromal cell differentiation presented quantitative but not qualitative modifications, the transformation of fibroblasts into myofibroblasts is quite likely, suggesting that myofibroblasts may be more closely related to fibroblasts than to smooth muscle cells.

Breast↗
PubMed1984

The intermediate filament proteins of rabbit normal epidermal Merkel cells are cytokeratins.

Four hundred Merkel cells (MC) have been studied by double-label immunofluorescence using: (1) a monoclonal antibody which has been previously demonstrated to react with MC and (2) antisera and monoclonal antibodies against the 5 types of intermediate filaments. It was demonstrated that MC did not react with vimentin, desmin, glial acidic fibrillary protein, or neurofilament antisera. A strong staining of MC was observed with 2 antisera and 2 monoclonal antibodies against keratin. The cytokeratin polypeptide pattern of MC is probably similar to that of simple epithelia. These findings attest to the epithelial nature of MC.

Animals↗
PubMed1984

Actin expression in smooth muscle cells of rat aortic intimal thickening, human atheromatous plaque, and cultured rat aortic media.

Actin of smooth muscle cells of rat and human aortic media shows a predominance of the alpha-isoform. In experimental rat aortic intimal thickening, in human atheromatous plaque, and in cultured aortic smooth muscle cells, there is a typical switch in actin expression with a predominance of the beta-form and a noticeable amount of gamma-form. This pattern of actin expression represents a new reliable protein-chemical marker of experimental and human atheromatous smooth muscle cells.

Actins↗
PubMed1984

Organization of actin cytoskeleton during early endothelial regeneration in vitro.

The pattern of early cell movement after an experimental 'wound' and the organization of actin in stationary and moving cultured endothelial cells have been studied by means of: time-lapse photography; indirect immunofluorescence using anti-actin antibodies with and without pretreatment with the actin destabilizing factor present in human plasma; and differential centrifugation and densitometric analysis of stained sodium dodecylsulphate/polyacrylamide gels in order to evaluate the total and relative amounts of G and F-actin. Up to 5 h after a single scratch, movement consists of a coordinate spreading and translocation of a band of about 10 cells from the wound edge. Compared to stationary cells, moving endothelial cells show: no significant changes in the intensity and distribution of immunofluorescent staining with anti-actin antibodies, but an increased sensitivity of cytoplasmic actin, including stress fibres, to the actin-destabilizing factor purified from human plasma; and no significant change in the total amount of actin, but a decreased relative amount of F-actin and a corresponding increased relative amount of G-actin. We conclude that endothelial cell movement in vitro is accompanied by a rapid change in the state of actin organization characterized by an overall decrease in cytoplasmic F-actin.

Actins↗
PubMed1984

Cytoskeleton of rat aortic smooth muscle cells. Normal conditions and experimental intimal thickening.

The organization of actin, vimentin, and desmin in smooth muscle cells of rat aortic media and intima under normal conditions and 15 or 75 days after endothelial injury has been studied by means of electron microscopy, indirect immunofluorescence, densitometric analysis of sodium dodecyl sulfate-polyacrylamide gels, isoelectric focusing, and bidimensional gels. In the normal aortic media, practically all smooth muscle cells contain vimentin, and about 50% of them contain, in addition, desmin; upon analysis of actin isotypes by bidimensional gels, smooth muscle cells show a predominance of alpha-actin, some beta-actin, and very little gamma-actin. Fifteen days after endothelial injury, cells that have migrated into the intima contain decreased amounts of actin and desmin and increased amounts of vimentin compared with normal medial smooth muscle cells. Moreover, beta-actin becomes the predominant actin isotype and significant amounts of gamma-actin appear, whereas alpha-actin decreases. Seventy-five days after endothelial injury, regenerated endothelial cells have repaired the injury. Intimal smooth muscle cells are less numerous than 15 days after injury, and the organization of their cytoskeletal elements has reverted almost to normal conditions. At both 15 and 75 days after endothelial injury, no significant changes of cytoskeletal elements are seen in the aortic media underlying intimal thickenings.

Actins↗
PubMed1983

Abnormal behavior of cultured fibroblasts from nodule and nonaffected aponeurosis of Dupuytren's disease.

Vimentin-positive, desmin-negative cells were established in culture from the nodule and from apparently normal palmar aponeurosis of a patient with Dupuytren's disease and compared with normal human embryonic and adult fibroblasts or sarcomatous cells. Cells from the nodule display in vitro biological properties that are intermediate between those expressed by normal fibroblasts and sarcoma cells or cells from the nodule transformed with SV40 virus. Thus, they represent an interesting in vitro model of partially transformed human cells. This behavior is not evolutive and justifies the classification of Dupuytren's disease among the benign mesenchymal tumors. The production of high level of plasminogen activator probably explains the local reactive pathology, and could act as a mitogenic stimulus for the proliferation of the nodule itself. Cultures derived from the apparently normal palmar aponeurosis show some but not all the abnormal growth properties of cells from nodules; this may help to explain the onset of local recurrences. Our results suggest that Dupuytren's disease is not strictly local and limited to the nodules, but affects, at least partially, the whole aponeurosis. Dupuytren's nodules could be considered as a model of tumor progression in a benign situation.

Blood↗
PubMed1983

Numerical densities of intramembrane particles in the cardiac sarcolemma of normal and myopathic Syrian hamsters.

The purpose of this study was to examine the density of intramembrane particles in the cardiac sarcolemma of normal and myopathic Syrian hamsters in a search for a morphological marker of a putative membrane defect. Hereditary cardiomyopathy in hamsters is manifested by progressive multifocal skeletal and cardiac muscle necrosis. Although pharmacological and biochemical data suggest a molecular defect in the cardiac sarcolemma, there has been no morphological observation that would substantiate this suggestion. We quantified numerical densities of intramembrane particles in freeze-fractured sarcolemmal membrane protoplasmic and extracellular faces from the left and right ventricular myocardium of female 25-day-old hamsters of the U.M.-X 7.1 cardiomyopathic line compared with sex- and age-matched randomly bred Syrian hamsters. Intramembrane particle numerical densities significantly increased above control values in cardiomyopathic hamsters for protoplasmic face (from 2188 +/- 61 to 2454 +/- 89 microns-2 in left ventricle (P less than 0.025) and from 2255 +/- 83 to 2574 +/- 56 microns-2 in right ventricle (P less than 0.001]. There was no significant difference between intramembrane particle densities of normal and cardiomyopathic hamsters for extracellular face (707 +/- 45 and 687 +/- 49 microns-2 in the left ventricle and 742 +/- 41 and 746 +/- 28 microns-2 in the right ventricle). These results implicate an increase of protoplasmic face-associated integral proteins in the sarcolemmal membrane of cardiomyopathic hamster. The significance of this finding is not known. It may represent an adaptive change related to a molecular defect in the sarcolemmal membrane of cardiomyopathic hamster.

Animals↗
PubMed1983

Organization of actin cytoskeleton in normal and regenerating arterial endothelial cells.

The distribution of actin stress fibers in normal and regenerating (after endothelial denudation by means of a balloon catheter) rabbit aortic endothelial cells has been studied by means of immunofluorescence with human actin autoantibodies on en face endothelial cell preparations. Our results show that: (i) under normal conditions actin is accumulated as a network at the periphery of endothelial cells. Stress fibers are present only in endothelial cells located immediately below intercostal artery branches; (ii) stress fibers develop in endothelial cells early during regeneration and persist after the end of endothelial mitotic and motile activities; and (iii) the orientation of stress fibers within the cytoplasm follows the direction of blood flow, with the exception of stress fibers situated in cells at the edge of the wound, when endothelial cell progression toward the denuded area as well as mitotic activity have ceased. We conclude that stress fibers are an organelle present in endothelial cells in vivo and that they reorganize during endothelial cell adaptation to unfavorable or pathological situations.

Actins↗
PubMed1983

Cytocontractile and cytoskeletal elements in pathologic processes. Pathogenetic role and diagnostic value.

The morphologic and biochemical characterization of cytocontractile and cytoskeletal elements in a given cell or tissue appears more and more as a useful tool in the study of differentiation phenomena, the origin of various human tumors (including metastases), and the degree of cellular adaptation during physiologic and pathologic processes. Thus, the biologic features of cytocontractile and cytoskeletal elements may be of practical interest to the pathologist and may furnish important information concerning basic cell responses during disease processes.

Cell Movement↗
PubMed1983

Remodeling of the rat aortic endothelial layer during experimental hypertension. Changes in replication rate, cell density, and surface morphology.

Three models of hypertension were induced in Wistar rats: (1) aortic ligature between renal arteries, (2) uninephrectomy and Na-rich diet, (3) uninephrectomy, 0.9 per cent NaCl as drinking fluid and subcutaneous administration of desoxicorticosterone acetate (DOCA). We studied the aortic endothelium during the early (7 to 10 days) and late (40 days) phases of these models and quantified: (1) thymidine index and cell density using autoradiography on en face preparations, and (2) internal aortic circumference by planimetry. We also examined by means of scanning electron microscopy the surface morphology of the aorta in rats with aortic ligature. Thymidine index was constantly increased in the early phases of all models; it reverted to normal levels in the late phases. Endothelial cell density was slightly but significantly increased in the early and late phases after aortic ligature and in the early phase after Na-rich diet; it increased strikingly in the early and late phases after DOCA. There were no significant correlations between the variations of the internal aortic circumference and blood pressure, thymidine index, or cell density. Scanning electron microscopy showed no discontinuity of the endothelial cell layer either in the early or late phases after aortic ligature; bulging of endothelial cells into the lumen and appearance of cell clusters with numerous surface projections were seen during the early phase after aortic ligature. These changes produce a remodeling of the aortic endothelial layer which is maximal in the early phase after aortic ligature and in the early and late phases after DOCA and correlates with the previously reported increase of endothelial permeability to horseradish peroxidase in the same hypertensive situations.

Animals↗
PubMed1983

Proteins of intermediate filaments. An immunohistochemical and biochemical approach to the classification of soft tissue tumors.

The intermediate filament cytoskeleton of various types of human soft tissue tumors was analyzed by immunofluorescence microscopy with the use of specific antibodies against cytokeratins, vimentin, and desmin, as well as by one- and two-dimensional gel electrophoresis of high-salt buffer- and detergent-resistant cytoskeletal preparations. All leiomyomas as well as a leiomyosarcoma contained desmin. Leiomyomas of both gastrointestinal and uterine derivation and the retroperitoneal leiomyosarcoma showed strong reaction for desmin in the smooth muscle cells, but the latter two exhibited also vimentin staining. In embryonal rhabdomyosarcomas, desmin prevailed in the large, apparently well-differentiated rhabdomyoblasts; whereas the smaller, less differentiated tumor cells preferentially contained vimentin. Cells of malignant fibrous histiocytomas were characterized by their content of vimentin as the only intermediate filament protein present. In alveolar soft part sarcoma, a rare tumor of hitherto unknown histogenesis, vimentin and desmin co-existed within the same tumor cells, indicating, together with chemical determinations, the myogenic derivation of this neoplasm. The results show that immunologic and biochemical analysis of proteins associated with the intermediate filament cytoskeleton is a useful adjunct in the diagnosis of diverse neoplasms, particularly those with equivocal histologic features, and thus aids in the histogenetic classification of soft tissue tumors.

Desmin↗